Experimental study on gallium activity in the liquid Ga–In–Tl alloys by EMF method with zirconia solid electrolyte

EMF of galvanic cells with zirconia solid electrolytes was measured to determine the activity of gallium in liquid Ga–In–Tl alloys in the temperature range of 950–1300 K along three pseudo-binary lines of (InyTl1 − y)–Ga where y = 0.25, 0.50 and 0.75. A mixture of Ga and Ga2O3 was used as a reference electrode. The activity curves of Ga show positive deviations from ideality in the whole composition range. Isoactivity curves at 1073 K in the ternary Ga–In–Tl alloys were derived by combining the activity data of Ga–In and Ga–Tl alloys. Excess free energy of mixing ΔGEx(=ΔG − ΔGideal) at 1073 K was derived by Darkenʹs equation using the binary data of In–Tl and ternary data in this study. The values in this study are smaller than those calculated from the general model calculation proposed by Chou.